In general, encapsulant materials such as underfill compositions can be used to provide mechanical enforcement between a semiconductor die, e.g., an integrated circuit (IC) die, and a substrate to form a package, e.g., an IC package. In IC packages such as a “flip chip” semiconductor device, a ball grid array (BGA) or a bump array, which can exploit the full surface area of the chip, is provided on a face of the die and bonded directly to solder connections on the substrate. The underfill composition provides mechanical enforcement between the die and the substrate by filling in the space between solder balls of the BGA or the bump array and then being cured. In addition to providing mechanical enforcement between the die and the substrate, the underfill composition can function to enhance the heat conduction out of the device when in the cured state.